No, attention deficit hyperactivity disorder (ADD/ADHD) cannot cause Alzheimer's or dementia. With ADD/ADHD, we’re dealing with a problem that has to do with the chemical dynamics of dopamine, a neurotransmitter responsible for movement and mood regulation, and norepinephrine, a neurotransmitter associated with "fight or flight" (your abilitiy to respond to stress), release at the brain’s synapses. With Alzheimer’s, the brain’s wiring is destroyed by a thick glop that accumulates on the neurons.

Are the symptoms I'm experiencing a result of Alzheimer's or is it ADD/ADHD?

I see women -- successful and smart -- come into my office and say, “I’m afraid I have Alzheimer’s, and it scares the crap out of me. I have trouble coming up with words that used to come easily. I can’t concentrate as well as I did.” I do the evaluation, and they have ADD/ADHD syndrome, but they don’t have a history of these difficulties before menopause. It makes sense, though, because estrogen is one of the primary modulators for the release of dopamine in the brain. As the estrogen level drops, as it does in menopause, the result -- for some women -- looks an awful lot like ADD/ADHD.

Thomas E. Brown, Ph.D., is assistant clinical professor of psychiatry at the Yale University School of Medicine, and associate director of the Yale Clinic for Attention and Related Disorders. He is author of the new book Smart but Stuck: Emotions in Teens and Adults with ADHD.